Freaking Work!!

I’m so frustrated!! I’ve repeatedly told my work that I will be working up until going into labor. I’m not being induced so nothing is scheduled and yet my boss has scheduled someone starting today. I’m 40 weeks today and no sign of labor in sight and our office is small so because the replacement will be there, there is literally nowhere for me to work. I did not want to use any of my vacation time before the baby comes but they’ve already submitted for my fmla which means if my baby comes late they’re cutting my time short with my little man!! I understand them wanting to be prepared with someone to come in - but to force me to take time off before I’m ready??